Pressurized fluid systems are typically provided with pressure relief capabilities to prevent the possibility of injury to humans and damage to equipment in the event of an overpressure situation. Such pressure relief systems often use a pressure responsive member that mechanically fails when subjected to a large increase in fluid pressure.
A particularly advantageous pressure relief system uses a buckling pin arrangement such as taught by U.S. Pat. No. 4,724,857 issued to Taylor. In such a system, the pin is placed under compressive load along an axial length of the pin by the pressure of the fluid. A sufficient increase in fluid pressure above a nominal operational level causes the pin to buckle, or collapse, allowing a plunger or other mechanism to move to a position where a bypass path can be established to direct the fluid to reduce the pressure to a safe operational level.
A valve can be advantageously configured to open or close in response to the collapse of a buckling pin, such as disclosed in copending U.S. patent application Ser. No. 10/020,611 filed by Taylor. Such a system uses a rotary actuator assembly with a rack and pinion arrangement. Lateral movement of the rack in response to a collapse of the pin induces rotation of the pinion. The pinion is coupled to the bypass valve to induce the desired rotary motion to open or close the valve.
While operable, under certain circumstances system forces can undesirably affect a threshold pressure level at which the pressure responsive member begins to fail. For example, friction forces and fluidic pressure can tend to offset the compressive load upon a buckling pin if the pin actuation and the valve are directly coupled.
There is therefore a continued need for improvements in the art to increase the accuracy and repeatability of pressure relief systems, and it is to such improvements that the present invention is directed.